Hot gas cleanup systems that are implemented to clean particulate matter from a gas stream are well known in the art. These systems are currently used to clean coal fired gas, (i.e. pressurized fluidized-bed combustion gas; gasification, applications), and waste incineration. Additionally, gas cleanup systems may be applied to catalyst and precious metal recovery, calcination, catalytic cracking, and material recovery during chemical processing.
Conventional hot gas cleanup systems generally comprise a filter assembly which is mounted within a pressure vessel having a clean gas side and a dirty gas side. The filter assembly further comprises a plurality of filter element arrays, a tube sheet for supporting the filter element arrays, plenum pipes for channeling filtered clean gas to a desired location within the cleanup system, and a back pulse system for cleaning particulates from the outer surface of the filter elements. These systems may employ various types of filter elements to filter particulate matter from a gas stream.
Typical filter elements employed to filter particulate matter include cross-flow filters, ceramic and/or sintered metal circular cylindrical filters (candle and/or tubular filters), and ceramic bag filters. These filter elements are generally mounted within a pressure vessel so that a hot gas can flow through the filter elements such that a substantial part of fine particulate matter within the process gas can be removed therefrom.
Typically, as a gas stream flows through a filter element, fine particulates collect on the outer surface of the filter elements while the clean gas flows through the filter media, into the plenum pipes, and out into the clean gas side of the pressure vessel. A substantial amount of the fine particulate matter that is collected on the outside of the filter is removed therefrom by a reverse gas pulse provided by the back pulse system.
During abnormal process operation, bridging of ash between adjacent filter elements and/or metal structures can occur. The bridging of ash can contribute to the failure or breakage of filter elements which would require that the entire system be shut down for days so that the filter elements can be replaced. It would therefore be desirable to provide a filter element and/or system that reduces the potential for bridging of ash.
Conventional filter arrays packaged within the pressure vessel may not optimally utilize the internal vessel space. It would therefore be desirable to provide a filter element that when optimally packaged within the pressure vessel will provide increased filtering surface area through which a gas can flow.
Additionally, conventional filters have the tendency to break or fracture because of the relatively heavy weight and geometry of the filters when being handled or manipulated within the cleanup system. It would therefore be desirable to provide a more robust and durable filter.